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Discussion Starter #1
I've been tweaking on the design of a Mopar cai I picked up a few weeks ago to reduce the hot air intrusion. I'm guessing it paid off, despite not being done with my fiddling yet..lol.

Here's the vid with the results. I have to say, it impressed me with how resistant it was to heat soak during hot lapping.

 

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Thanks for the video but I don't believe you proved anything. The reason is you didn't provide much info on how you made the comparison. When did you run the Hellcat air box because you never showed it? It appears you are comparing your car to another car with the Hellcat air box. If so that's apples to oranges. You didn't show the ET for the Hellcat air box which is what drag racing is all about and not speed at the end of the run. Quite often you will get lower speed with faster ET. I ran 11.979 @ 112.1 mph when I was bone stock. Please try again with a more scientific comparison or explain how the comparison was made.
 

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Discussion Starter #4
Actually, it was a direct apples to apples comparison. He was on the same tires, Hellcat air box and intake tube, filter removed, and adaptives reset. Only difference was the tweaked Mopar cai, and he doesn't have a catch can yet. The fact I out trapped him on EVERY pass kind of lends credence to the Mopar cai working better. We even had a pass that I spun, car short shifted to 2nd, bogged a bit, and still managed to run him down.

The real kicker is this. I ran 11.973 @ 116.03 (1.774 60 ft) on the stock 245 F1 tires with the Hellcat airbox/tube, in -300 DA air. I ran a 12.37 @ 115.3 (1.91 60ft) in 1600 DA, then a 12.28 @ 115.75 (1.887 60ft) in 900 to 1000 DA. 1900 ft difference in DA on one run, and 1200-1300 DA difference on the other....but the car trapped within 1 mph or less of it's all time best. ET is great, but trap speed is the measure of horsepower. That data tells me the tweaked Mopar cai, with the filter in place, is the better performer vs the HC setup with filter removed.

Another point to ponder....why did my car trap 114+ when hot lapped 4 consecutive passes, when prior to that, it would drop 1-2 mph every pass. Heat soak, that's why. Still a minor issue with the tweaked Mopar, but much less than before.
 

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Well the apples to oranges is that you are comparing 2 different cars. I haven't seen any time slips for you and your friend. How did you determine the right lane was 2 mph low? Maybe the left lane was 2 mph high. I raced at Montgomery one time when the left lane was 5 mph high. Some guy in a mustang was telling me he trapped at 116 mph when I trapped at 113 and beat him walking away. My mph gauge and also a Corvette agreed with me it was the left lane reading 5 mph high.
Your second paragraph is a jumbled mess. I'm guessing it was all done on different days and not the same day under changing conditions.
For the third paragraph I would have to see the time slips to make any sense of it. Hot lapping in 85 degree temp is a lot different than hot lapping in 60 deg temp. None of your info presented here can really be argued for or against in my opinion.
If you are convinced you are correct in your conclusions then nothing I can say will make any difference. I can only say there is not enough actual facts here to draw any real conclusion.
 

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Discussion Starter #6
Well the apples to oranges is that you are comparing 2 different cars. I haven't seen any time slips for you and your friend. How did you determine the right lane was 2 mph low? Maybe the left lane was 2 mph high. I raced at Montgomery one time when the left lane was 5 mph high. Some guy in a mustang was telling me he trapped at 116 mph when I trapped at 113 and beat him walking away. My mph gauge and also a Corvette agreed with me it was the left lane reading 5 mph high.
Your second paragraph is a jumbled mess. I'm guessing it was all done on different days and not the same day under changing conditions.
For the third paragraph I would have to see the time slips to make any sense of it. Hot lapping in 85 degree temp is a lot different than hot lapping in 60 deg temp. None of your info presented here can really be argued for or against in my opinion.
If you are convinced you are correct in your conclusions then nothing I can say will make any difference. I can only say there is not enough actual facts here to draw any real conclusion.
It's well known that the right lane in Gainesville is normally 2-3 mph slower than the left, at least when it comes to the 1/4 mile traps. 1/8 mile timers are spot on, but for whatever reason, the top end timers are off. That's one of several reasons I'm not particularly fond of going to Gainesville for T&T. But, it's the closest track to me, so take what I can get until I make another trip to Orlando Speed World. I was watching the speedo as well, and going off that to correct the right lane runs. It's annoying, to say the least.

I was trying to type and troubleshoot a production line, so it may have gotten a bit jumbled. What I was saying is the car had near identical trap speeds, in very different conditions. The 11.97 @ 116 pass on the Hellcat box/tube came on a night where the DA was hovering between -300 to -450. The DA at Gainesville started at +1600 and dropped to between +900 to +1000. Even with the higher DA, the car still ran within 1 mph of the best pass to date. The difference between the conditions was significant, ranging from +1900 to +1200 in DA. That's significant, given that I've normally seen a 1 mph loss/gain for every 700 to 750 ft change in DA. The ONLY change to the car was the Mopar cai....that's it. I didn't even clear the adaptives this time, so she was running on the driving parameters from the trip to the track. I'm hoping to make a trip to Orlando to test the two intakes heads up, and at a facility where everything works as it should. Mother Nature has been less than cooperative with my plans, unfortunately. If the rain keeps up, I'll be testing a snorkel kit for the car..lol.

The hot lapping is what really surprised me. Air temp at the time was 74* by the dash display, and IAT would drop within 2-3* of ambient about 300-400 ft out from the starting line. With the Mopar, I saw the initial drop from 1st to 2nd runs, as expected. But, from runs 2-3, 3-4, there was only .5 mph difference in total. Run 1....115.76, Run 2...114.39, Run 3...114.86, Run 4...114.34. The runs were 5-6 mins apart, with the only cool down being what air ran across the filter driving back to staging. I was intentionally trying to induce heat soak, but the car stayed consistent after that initial drop off.

The last time I ran the HC setup was at Gainesville on May 7th, and I saw a drop every pass. 3 passes, within 20 mins, and here are the trap speeds. Run 1....115.02, Run 2....114.05, Run 3....113.52. These were on a breezy 67* day, with DA of 1302. 1st and 2nd runs were 7 mins apart, but 2nd to 3rd were 18 mins apart. While in line for the 3rd pass, I had the hood up while moving up the staging lanes , but it did little to cool the HC air box down. Once that plastic air box gets heat soaked, it takes a long while for it to cool down.

As for the comparison between my car and the other Scat Pack, it really was a good measuring stick. Gene's car is a '16 like mine, A8 trans, 275/40 Atturo AZ850 tires. He had the HC lower with inlet tube, same as I had before. He was running no filter, cleared the PCM adaptives, 26# air in the rears. 1st pass we made together, he was in the left lane....ran a 12.958 @ 112.49 to my 12.297 @ 115.75. He had a 2.201 60ft to my 1.886....couldn't believe I got the car to somewhat hook. 2nd pass....my 12.332 @ 114.39 to his 13.021 @ 112.03. 3rd pass....my 12.939 @ 114.86 to his 12.910 @ 113.33. He had me beat at the 1/8 mile, but I pulled past him on the top end. The heat soak was causing the PCM to pull performance back, whereas my car still had a top end charge. We had a good laugh about the last run, because he thought he had me beat....then I came by him just before the traps and spoiled his fun...lol.

I'll get the time slips scanned into my computer and post them up for comparison. It may take a day or two, still have one more shift to go before a day off. I'm constantly looking at past slips, trying to figure out if there is more gains to be had...checking weather data to plan track visits...thinking about launch rpm, tire pressures, etc. If the liquid sunshine will stay away this weekend, hoping to make it to Orlando for more testing of the two intakes. Head to head, same track, same conditions. But, so far, the tweaked Mopar is holding a decent edge over the Hellcat setup, at least in my experience.
 

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Well don't do the time slips for my sake. My whole point of this discussion is that there will be literally no difference in the temp of the cold air coming from each CAI input. Also I remember one of the sponsors here saying they would do a comparison with a CAI vs the stock CAI that comes with the Scatpack and report the difference. Since they are trying to sell the CAI I expected them to report the difference if it was favorable to the new CAI. I never saw a report which led me to believe there was little or no difference. Bottom line is if you want to do a real test you need to do it on a Dyno on the same car/same day. That way most of the (many) variables will be eliminated.
 

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Here is what I had done on same day on the all wheel dynojet on my 07 srt8 jeep. The test was done with 91 octane mobil gas.
1- Bone stock HP 341 TQ 352. 1/8 mile best et 8.39 @ 81.72 race wt 5190 lbs
2- Added cai HP 348 TQ 356. No tuning yet.
3-Tuning started HP 362 TQ 376 (dyno guy wasn't happy so he found the tuner needed updated)
4-Tuning continued with updated tuner HP 368 TQ 382. Race day 1/8 mile best et 8.16 @ 83.92. All runs on 91 octane.
5-Added a 50/50 4 gal mix of 91 and vp109 ( 98 octane with mix ) with no tuning for the race gas on this Race day. Best 1/8 mile et 7.95 @ 85.70.
 

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Here is what I had done on same day on the all wheel dynojet on my 07 srt8 jeep. The test was done with 91 octane mobil gas.
1- Bone stock HP 341 TQ 352. 1/8 mile best et 8.39 @ 81.72 race wt 5190 lbs
2- Added cai HP 348 TQ 356. No tuning yet.
3-Tuning started HP 362 TQ 376 (dyno guy wasn't happy so he found the tuner needed updated)
4-Tuning continued with updated tuner HP 368 TQ 382. Race day 1/8 mile best et 8.16 @ 83.92. All runs on 91 octane.
5-Added a 50/50 4 gal mix of 91 and vp109 ( 98 octane with mix ) with no tuning for the race gas on this Race day. Best 1/8 mile et 7.95 @ 85.70.
Nice to know info. Let me point out a couple of possible problems with your info.
1. Your bone stock numbers were without your dyno guy trying to see how much power was still available in the stock tune.
2. So the numbers starting with the stock tune only added 7hp/4Lbft. Any tuning after that point could be partially because the stock tune left hp available.
3. & 4. Nice to see tuner was not up to par but fixed.
5. Interesting info but not pertinent. (adding CAI cannot take credit for what vp109 does)
Did the Jeep come with a CAI? If not all of your info has nothing to do with comparing one CAI to another CAI.
Pretty much everyone agrees that adding a CAI to a car that doesn't have one will add hp.
 

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Nice to know info. Let me point out a couple of possible problems with your info.
1. Your bone stock numbers were without your dyno guy trying to see how much power was still available in the stock tune.
2. So the numbers starting with the stock tune only added 7hp/4Lbft. Any tuning after that point could be partially because the stock tune left hp available.
3. & 4. Nice to see tuner was not up to par but fixed.
5. Interesting info but not pertinent. (adding CAI cannot take credit for what vp109 does)
Did the Jeep come with a CAI? If not all of your info has nothing to do with comparing one CAI to another CAI.
Pretty much everyone agrees that adding a CAI to a car that doesn't have one will add hp.
1- He made 3 pulls with stock tune.
2- He made 3 pulls with cai.
5- The jeep had stock air box when stock dyno tune was run. I see what you mean about the cai to cai but the stock air box is some sort of cai..
 

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Couldn't you just bring both intake setups and swap them back and forth at the track, like A B A B testing within 1-2 hour timeframe?

If the car is already hot and heatsoaked, it should be running about the same. Make two passes with the hellcat airbox, then one pass with the Mopar CAI, then another pass hellcat airbox, then one more with the Mopar CAI. Provided there are no major variables between the passes like the temp dropped significantly, sudden headwind, etc I would think you would see a trend.

From what I have seen, the hellcat airbox seems to be the best all around setup for our cars. Even some of the fastest Hellcats running in the 9's are still using it. Perhaps there is a small gain, but it doesn't seem justified given the amount of $$ spent on it. The hellcat airbox cost me $85 vs a Mopar CAI costing $300-400 for essentially the same approximate gains.
 

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Couldn't you just bring both intake setups and swap them back and forth at the track, like A B A B testing within 1-2 hour timeframe?

If the car is already hot and heatsoaked, it should be running about the same. Make two passes with the hellcat airbox, then one pass with the Mopar CAI, then another pass hellcat airbox, then one more with the Mopar CAI. Provided there are no major variables between the passes like the temp dropped significantly, sudden headwind, etc I would think you would see a trend.

From what I have seen, the hellcat airbox seems to be the best all around setup for our cars. Even some of the fastest Hellcats running in the 9's are still using it. Perhaps there is a small gain, but it doesn't seem justified given the amount of $$ spent on it. The hellcat airbox cost me $85 vs a Mopar CAI costing $300-400 for essentially the same approximate gains.
What are yours mods to achive that 11.6?

My best is 12.01 @ 114

HC Intake / Tazer / Stock Tires :surprise:
 

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I agree the Hellcat air intake with Hellcat paper OEM style filter is a bang for the buck excellent mod!
Here is something to consider. Five runs on one night 1/8 mile.
1st run DA 2515 ft 60 ft. 2.09" 1/8 mile 8.058 @ 92.7 mph
2nd run DA 2439 ft 60 ft. 2.01" 1/8 mile 8.027 @91.42 mph
3rd run DA 2282 ft 60 ft. 2.07" 1/8 mile 8.107 @ 92.13 mph
4th run DA 2100 ft 60 ft. 2.01" 1/8 mile 7.96 @ 93.05 mph
5th run DA 1982 ft 60 ft. 2.03" 1/8 mile 8.06 @ 92.12 mph

On the last run I blocked the Hellcat intake mod with a plug made from a paint spray can top. What conclusion would you draw from those statistics considering the Hellcat mod?
 

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Discussion Starter #17
In what way did you modify your mopar CAI?
Besides getting the correct Mopar inlet tube for the headlight bucket, I did two things. One....I spaced it up from the bottom about 1/2" to get the rubber perimeter seal against the hood, or VERY close to it. Two...and this is the other big thing...I made a block off for the cut out along on the front edge. That opening allows a lot of hot air to seep in at idle/low speed, so did my best to block that bugger off. I haven't tinkered with it much lately though. Mother Nature has been in a foul mood on race days lately...lol. It's either a few degrees short of volcanic, or raining hard enough to drown a frog.

I'm also going to lighten the load a bit on the car.....JMS 17x10 rears are here, now need to order my fronts and decide on tires. I was going to jump on a Procharger deal I found, but decided to stay N/A, pay off a few bills, and see how far the stock tune will take me before getting in touch with Hemifever to really cut her loose.
 

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Discussion Starter #18
Couldn't you just bring both intake setups and swap them back and forth at the track, like A B A B testing within 1-2 hour timeframe?

If the car is already hot and heatsoaked, it should be running about the same. Make two passes with the hellcat airbox, then one pass with the Mopar CAI, then another pass hellcat airbox, then one more with the Mopar CAI. Provided there are no major variables between the passes like the temp dropped significantly, sudden headwind, etc I would think you would see a trend.

From what I have seen, the hellcat airbox seems to be the best all around setup for our cars. Even some of the fastest Hellcats running in the 9's are still using it. Perhaps there is a small gain, but it doesn't seem justified given the amount of $$ spent on it. The hellcat airbox cost me $85 vs a Mopar CAI costing $300-400 for essentially the same approximate gains.
I thought about doing some B2B testing, but last time I went to the track with both setups, we got rained out before I could test them. I haven't been back to the track since the night I ran the 12.3 @ 115.3 and 12.2 @ 115.7.....mother nature has been conspiring against me. Rain has been the biggest issue....never fails to rain on T&T day, and only in the area of the track...lol. Gainesville (closest track to me-1 hr drive) is inconsistent with prep on T&T days, and Orlando Speed World (much better track-2 hrs away) has been hit and miss with rain. At some point, I will run these two against each other. But, like I mentioned in the early post, I did run against another A8 Scat Pack, same night/conditions/tires...and was consistently 1-3 mph faster. When I spun and still ran him down, that was the proof I needed that it was working..somehow, someway, it helped going from the HC box to the Mopar setup. One gigantic difference....not running unfiltered air into the engine. That was the one thing about the HC setup that always bothered me.

Cost wise....well, I did get my Mopar setup used, so it was a lot cheaper than a new one. I honestly think they are a bit overpriced for that they are, especially not having the inlet tube or a block off plate for that giant square cutout included. I still can't figure out why it's doesn't come with a block off plate...just a stupid design oversight IMO.
 

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Just as a FWIW...I've used this approach on a couple cars with good results...

Mine is a stock SRT airbox...Covered, top and sides with Reflectix, a heat shield..
Object to keep some of the engine compartment heat from effecting temp of incoming air...
Knocks off a couple degrees...

 

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Besides getting the correct Mopar inlet tube for the headlight bucket, I did two things. One....I spaced it up from the bottom about 1/2" to get the rubber perimeter seal against the hood, or VERY close to it. Two...and this is the other big thing...I made a block off for the cut out along on the front edge. That opening allows a lot of hot air to seep in at idle/low speed, so did my best to block that bugger off. I haven't tinkered with it much lately though. Mother Nature has been in a foul mood on race days lately...lol. It's either a few degrees short of volcanic, or raining hard enough to drown a frog.

I'm also going to lighten the load a bit on the car.....JMS 17x10 rears are here, now need to order my fronts and decide on tires. I was going to jump on a Procharger deal I found, but decided to stay N/A, pay off a few bills, and see how far the stock tune will take me before getting in touch with Hemifever to really cut her loose.

Here's a pic of mine, is this the hole in the front you blocked off? Won't that block cool air coming from the gap in headlights?

 
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